A11y: Add a browser test of TrayAccessibility.

ash/system/tray/system_tray.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/system/tray/system_tray.h"
 
 #include "ash/ash_switches.h"
 #include "ash/shell.h"
 #include "ash/shell/panel_window.h"
 #include "ash/shell_window_ids.h"
@@ skipping 113 matching lines @@
 
 void SystemTray::InitializeTrayItems(SystemTrayDelegate* delegate) {
   internal::TrayBackgroundView::Initialize();
   CreateItems(delegate);
 }
 
 void SystemTray::CreateItems(SystemTrayDelegate* delegate) {
   AddTrayItem(new internal::TrayLogoutButton(this));
   AddTrayItem(new internal::TrayUser(this));
   AddTrayItem(new internal::TrayIME(this));
-  AddTrayItem(new internal::TrayAccessibility(this));
+  tray_accessibility_ = new internal::TrayAccessibility(this);
+  AddTrayItem(tray_accessibility_);
   AddTrayItem(new internal::TrayPower(this));
 #if defined(OS_CHROMEOS)
   AddTrayItem(new internal::TrayNetwork(this));
   AddTrayItem(new internal::TrayVPN(this));
   AddTrayItem(new internal::TraySms(this));
 #endif
   AddTrayItem(new internal::TrayBluetooth(this));
   AddTrayItem(new internal::TrayDrive(this));
   AddTrayItem(new internal::TrayLocale(this));
 #if defined(OS_CHROMEOS)
@@ skipping 394 matching lines @@
         ConvertPointToWidget(this, &point);
         arrow_offset = point.x();
       }
     }
     ShowDefaultViewWithOffset(BUBBLE_CREATE_NEW, arrow_offset);
   }
   return true;
 }
 
 }  // namespace ash